Returning a DataTable using Entity Framework ExecuteStoreQuery

Question

I am working with a system that has many stored procedures that need to be displayed. Creating entities for each of my objects is not practical.

Is it possible and how would I return a DataTable using ExecuteStoreQuery ?

public ObjectResult<DataTable> MethodName(string fileSetName) {
using (var dataContext = new DataContext(_connectionString))
{
var returnDataTable = ((IObjectContextAdapter)dataContext).ObjectContext.ExecuteStoreQuery<DataTable>("SP_NAME","SP_PARAM");
return returnDataTable;
}

Solution 1

No, I don't think that'll work - Entity Framework is geared towards returning entities and isn't meant to return DataTable objects.

If you need DataTable objects, use straight ADO.NET instead.

Solution 2

Yes it's possible, but it should be used for just dynamic result-set or raw SQL.

public DataTable ExecuteStoreQuery(string commandText, params Object[] parameters)
{
    DataTable retVal = new DataTable();
    retVal = context.ExecuteStoreQuery<DataTable>(commandText, parameters).FirstOrDefault();
    return retVal;
}

Edit: It's better to use classical ADO.NET to get the data model rather than using Entity Framework because most probably you cannot use DataTable even if you can run the method: context.ExecuteStoreQuery<DataTable>(commandText, parameters).FirstOrDefault();

ADO.NET Example:

public DataSet GetResultReport(int questionId)
{
    DataSet retVal = new DataSet();
    EntityConnection entityConn = (EntityConnection)context.Connection;
    SqlConnection sqlConn = (SqlConnection)entityConn.StoreConnection;
    SqlCommand cmdReport = new SqlCommand([YourSpName], sqlConn);
    SqlDataAdapter daReport = new SqlDataAdapter(cmdReport);
    using (cmdReport)
    {
        SqlParameter questionIdPrm = new SqlParameter("QuestionId", questionId);
        cmdReport.CommandType = CommandType.StoredProcedure;
        cmdReport.Parameters.Add(questionIdPrm);
        daReport.Fill(retVal);
    }
    return retVal;
}

Solution 3

This method uses the connection string from the entity framework to establish an ADO.NET connection, to a MySQL database in this example.

using MySql.Data.MySqlClient;

public DataSet GetReportSummary( int RecordID )
{
    var context = new catalogEntities();

    DataSet ds = new DataSet();
    using ( MySqlConnection connection = new MySqlConnection( context.Database.Connection.ConnectionString ) )
    {
        using ( MySqlCommand cmd = new MySqlCommand( "ReportSummary", connection ) )
        {
            MySqlDataAdapter adapter = new MySqlDataAdapter( cmd );
            adapter.SelectCommand.CommandType = CommandType.StoredProcedure;
            adapter.SelectCommand.Parameters.Add( new MySqlParameter( "@ID", RecordID ) );
            adapter.Fill( ds );
        }
    }
    return ds;
}

Solution 4

Yes it can easily be done like this:

var table = new DataTable();
using (var ctx = new SomeContext())
{
    var cmd = ctx.Database.Connection.CreateCommand();
    cmd.CommandText = "Select Col1, Col2 from SomeTable"; 

    cmd.Connection.Open();
    table.Load(cmd.ExecuteReader());
}

Solution 5

By the rule, you shouldn't use a DataSet inside a EF application. But, if you really need to (for instance, to feed a report), that solution should work (it's EF 6 code):

    DataSet GetDataSet(string sql, CommandType commandType, Dictionary<string, Object> parameters)
    {
        // creates resulting dataset
        var result = new DataSet();

        // creates a data access context (DbContext descendant)
        using (var context = new MyDbContext())
        {
            // creates a Command 
            var cmd = context.Database.Connection.CreateCommand();
            cmd.CommandType = commandType;
            cmd.CommandText = sql;

            // adds all parameters
            foreach (var pr in parameters)
            {
                var p = cmd.CreateParameter();
                p.ParameterName = pr.Key;
                p.Value = pr.Value;
                cmd.Parameters.Add(p);
            }

            try
            {
                // executes
                context.Database.Connection.Open();
                var reader = cmd.ExecuteReader();

                // loop through all resultsets (considering that it's possible to have more than one)
                do
                {
                    // loads the DataTable (schema will be fetch automatically)
                    var tb = new DataTable();
                    tb.Load(reader);
                    result.Tables.Add(tb);

                } while (!reader.IsClosed);
            }
            finally
            {
                // closes the connection
                context.Database.Connection.Close();
            }
        }

        // returns the DataSet
        return result;
    }

View more solutions

Comments

[user2067567]

Am not seeing Connection property for Context ? am i missing something ?

[Hoppe]

What is this global object? Not sure where you are getting it from. Is it from Web Api 2?

[sedavidw]

For DbContext, it is context.Database.Connection.

[Dai]

@Hoppe MetaTable and DefaultModel (an instance of MetaModel) are part of ASP.NET DynamicData, essentially a scaffolding framework. It isn't related to Entity Framework so I don't think this is a useful answer at all.

[Tony]

Very nice. I modified this slightly public static DataSet GetDataSet(this DbContext context, string sql, CommandType commandType, Dictionary<string, Object> parameters)

[Bill Clyde]

If you are using Entity Framework and you just need to run an odd query that doesn't match any entity, you can do so through the context Database property. That gets you to the ADO.NET layer. Some of the other answers reflect this.

[Jakotheshadows]

nice, how about with parameters?

[CodingYoshi]

@jakotheshadows cmd is a SqlCommand object so you'd do it as regular e.g. cmd.Parameters.AddWithValue("@param", whatever);

[Jakotheshadows]

For me it ended up being a DbCommand abstract class which was what was tripping me up at first. But it makes sense if that's true because SqlCommand is derived from DbCommand.

[vapcguy]

Only one note: Anyone sending in an UPDATE query with parameters - ensure that, of the parameters you send, none are empty strings. If they are, do some checking via code before sending your query to this function, in order to edit that field out of the query and don't send that parameter. Even though my field was not a NOT NULL field, it behaved that way when trying to update it with an empty string parameter using this, because the field was specified in the query as receiving an update.

[Jonathan Stark]

Anyone sending in an UPDATE command to this function - think again - this is intended for reading data into a DataTable, not for updates

[vapcguy]

Yes, that is, reading data FROM a DataTable, you meant, yes. I changed it so instead of that whole ExecuteReader section, I was doing a cmd.ExecuteScalar(); to send the update. As a result my comment was probably offbase, as I had made that function a void instead of returning a DataTable. I also was using this one, too, and I think I got them confused when I made my comment.